1. Field of the Invention
The present invention relates to an image processing method of converting gradation information on an image of a substrate picked up in an inspection apparatus, and to an image display method, an image processing apparatus, and a computer storage medium.
2. Description of the Related Art
In a photolithography process in manufacturing process of a semiconductor device, for example, a series of treatments such as a resist coating treatment of applying a resist solution onto a wafer to form a resist film, exposure processing of exposing the resist film into a predetermined pattern, a developing treatment of developing the exposed resist film and so on are performed in sequence to form a predetermined resist pattern on the wafer. A series of these treatments are performed in a coating and developing treatment system being a substrate treatment system in which various treatment units treating the wafer treating the wafer, transfer mechanisms transferring the wafer and so on are installed.
The wafer for which a series of photolithography treatments have been performed in the coating and developing treatment system is subjected to a so-called macro defect inspection by a defect inspection apparatus, as to whether or not a predetermined resist film has been formed on the front surface of the wafer, or whether or not there is a scratch or adherence of foreign substance.
In such a macro defect inspection, while a mounting table on which the wafer is mounted is being moved, illumination is applied to the wafer on the mounting table and, for example, an imaging device of a CCD line sensor picks up an image of the front surface of the wafer. Then, the presence or absence of defects on the front surface of the wafer is determined based on the picked-up image. In this event, if the luminance (pixel value) of the picked-up image is too high or too low, the defects on the wafer cannot be determined in some cases. Therefore, to bring the luminance of the image of the wafer to an optimal luminance for defect determination, the illuminance of the illumination illuminating the wafer is adjusted (Patent Document 1).    Patent Document 1: Japanese Laid-open Patent Publication No. 2009-216515